Most of what you're going to be doing as treasurer is bringing in
receipts, most of which will be for our weekly movies. The way this
works is that you bring the receipt to BC during office hours (which
should be posted on the door, or appear at the bottom of any email you
receive from BC 
bctreas1@swarthmore.edu
). You then fill
out a transaction form with the date, organization name and account
number, item(s), relevant event name and date (for movies, I usually
put, e.g., ``Weekly movie 3/13''), subcode and amount, who the check
should go to, and your signature. You want a personal check, not a
paycheck. If you have multiple receipts from the same person, you can
put them all on one transaction form, but if you need multiple checks
issued, you need that many forms. You can usually get them to print
the check for you right then, but sometimes if they're really busy
they'll ask if they can send it via campus mail. This works fine and
doesn't take too long.
Tips and things to watch out for: It's a good idea to put the name of the person you got a receipt from on the back of it, so you don't forget who it's for. (This can happen if you have half a dozen receipts.) Also, all receipts need to be in by the end of the semester, so make sure you watch out for that deadline, or some of your friends will be out money and not happy with you. But you're better off bringing them in every week or two, because then BC gets to know you, and remember: You Want Budget Committee to Like You (tm). Finally, get to office hours early, so you can just get in, fill out the forms you need, and get out. A very long line tends to build up towards the end of office hours, and waiting in it sucks.